Buttonhole-sewing machine



June 7, 1966 H. PUDELKO BUTTONHOLE-SEWING MACHINE 4 Sheets-Sheet 1 Filed Dec. 9, 1963 HfRM/l/V/V PUDtL K0 INVENTOR.

AGENT 4 Sheets-Sheet 2 Filed Dec. 9, 1963 AGENT June 7, 1966 H. PUDELKO BUTTONHOLE-SEWING MACHINE 4 Sheets-Sheet 5 Filed Dec. 9, 1963 Hf/iW/J/V/V PUDEZ K0 INVENTOR.

June 7, 1966 H. PUDELKO BUTTONHOLE-SEWING MACHINE 4 Sheets-Sheet 4 Filed Dec. 9, 1963 INVENTOR.

AGENT.

United States Patent r 3,254,616 BUI'IONHOLE-SEWING MACHINE Hermann Pudelko, Bielefeld, Germany, assignor to Durkoppwerlre A.G.

Filed Dec. 9,1963, Ser. No. 328,938 Claims priority, application Germany, Dec. 7, 1962,

6 Claims. (a. 112-65) My present invention relates to a buttonholesewing machine of the type wherein a throat plate is carried on a rotatable turret, e.g., as disclosed in U.S. Patents Nos. 1,787,928 and 1,877,159, the throat plate being provided with an opening at a location aligned with a reciprocating needle carrying an upper thread which, in the course of a sewing operation, is concatenated with an under- I thread to form a buttonhole seam on a workpiece of fabric or the like. Rotation of .the turret and its throat plate about a vertical axis, at the end of each seam-forming operation, serves to reverse the relative position of the stitch-forming means on the turret and the fabric-clamp ing means on the machine bed so that a second seam The general object ofmy invention is to provide means for releasably retaining the end of the severed underthread (and, preferably, also that of the stay cord) in a position relative to the throat plate in which it will be positively entrained by the stitch-forming means during the first stitch of the next sewing step.

Another object of this invention is to provide clamping means for the purpose set forth which can be conveniently adjusted to accommodate underthreads and/ or stay cords of different thickness.

The foregoing objects are realized, in accordance with this invention, by the provision of a throat plate with a slot for the underthread and a channel for the stay cord both terminating at the sewing opening of the plate, the slot having an entrance end so dimensioned as to be wide enough to admit the underthread but sufiiciently restricted to block the stay cord when the turret is rotated back into its starting position. Advantageously, the underthread-receiving slot has a slit-shaped outlet which-merges with the inlet of the cord-receiving channel, a resilient clamping element being so disposed at the slot outlet that one portion of this element cooperates with an edge of the slit to'engage the underthread whereas another portion of that element separates the slot from the channel, thereby preventing the entry of the underthread into the channel, and also exerts some friction upon the stay cord (if present in the channel).

The above and other features of my invention will become more fully apparent from the following detailed description of a preferred embodiment, reference being made to the accompanying drawing in which:

FIG. 1 is a side-elevational view of buttonhole-sewing machine of the general type described above;

FIG. 2 is a top view taken substantially along the line IIII of 'FIG. 1;

FIG. 3 is a view similar to FIG. 2, with parts removed to expose the underlying mechanism;.

FIG. 4 is a top plan view, drawn to a larger scale, of a throat plate forming part of the mechanism of FIG. 3;

FIG. 5 is a side-elevational view of the throat plate shown in FIG. 4;

Patented June 7, 1966 "Ice FIG. 6 is a fragmentary cross-sectional view taken on the line ICIV of FIG. 4; and

FIG. 7 is a prospective view of the throat plate and associated thread-guiding means.

The machine shown in FIGS. 1-3 is generally of the type shown in the aforementioned U.S. patents and carries the usual tools for the sewing of buttonholes, including a vertically reciprocable and laterally swingable needle 1 whose alternate positions relative to an associated throat plate Shave been shown in solid and dot-dash lines in FIG. 7. A pair of work clamps 30 serve to hold a fabric 31 against the machine bed 32 for the sewing of a buttonhole seam 25. The seam 25 is formed by an upper thread 2, entrained by the needle 1, and an underthread 4 delivered to the plate 8 by the-usual supply means including a looper-type gripper 3. The seam 25 also incorporates a stay cord or gimp 6 whose supply mechanism is partly visible at 33. A cutter 5 slits the buttonhole after the formation of seam 25 has been completed.

The throat plate 8 is supported on a rotatable turret 7; its initial position realtive to the work 31 and the clamps 30 is shown in FIGS. 2 and 3, the turret 7 and the plate 8 being rotated through 180 after the first half of the seam 25 has been formed. It will be noted that, in the illustrated position, the cord 6 is supplied to the plate 8 around an idler roller 33' from the general direction of the cutter 5 toward which the fabric 31 is advanced by the work-feeding mechanism of the machine upon completion of a buttonhole-sewing and thread-severing operation.

As best seen in FIGS. 4-7, the throat plate 8 is provided with a stitch opening 8' which defines a sewing location and receives the needle 1 in its two alternate positions 1', 1" (FIG. 4), this opening communicating with a horizontal channel 8" for the cord 6 and with a slot 10 also formed approximately horizontally within the plate 8. Plate 8 is recessed at 9 to expose a transverse shoulder 9, both the inlet of channel 8 and theslit-shapedoutlet of slot 10 opening onto this shoulder as best seen in FIGS. 6 and 7. As clearly apparent from FIG. 6, slot 10 merges with channel 8" and is of considerably reduced width in comparison therewith so as freely to accommodate the underthread 4 while blocking the entry of cord 6. The entrance end 10' of slot 10 extends arcuat ely on the .upper surface of plate 8 and is defined by a pair of lips 12 and 13, lip 12 merging at 12 with a peripheral guiding edge 14 of opening 8 (facing the exit of channel 8" into that opening) whereas lip 13 joins at a point 13 another guiding edge 15 (adjacent the channel exit) which extends generally parallel to shoulder 9. The outlet of slot 10 is defined by two horizontal edges 19, 20. v I

A clamping element 16 in the form of a wire spring adjoins the shoulder 9' and is angularly bent to form a horizontal portion 16a, a generally vertical portion 16b and a transverse portion extending at right angles to shoulder 9', the latter portion being adjustably received in a bore 17 of plate 8 and being immobilized therein by a setscrew 17' (FIG. 4). Spring portion 16a cooperates with the upper edge 19 at the outlet of slot 10 for clamping engagement with an end 4' of the underthread 4 after the latter has been severed by a cutter assembly 24; this assembly also severs the cord 6 whose end 6 may thereafter be retracted, by a suitable tensioning device forming part of the supply means 33, to a point within or just above opening 8' as shown in FIG. 7. Spring portion 16b bears with light pressure upon the cord 6 in channel 8" so as to exert some control upon this withdrawal. The clamping pressure of spring 16 is adjustable by means of the fastening screw 17'.

In operation, buttonhole seam 25 is sewn in the usual manner with consecutive rotations of turret 7 and plate 8 in the clockwise direction as viewed in FIGS. 24. The supply mechanism for underthread 4 also includes a friction brake 22 (FIG. 1) maintaining this thread under a certain tension on its passage through the opening 8; cord 6, on the other hand, is movable with only slight friction past spring portion 1611 via channel 8" through the plate opening 8'. When, upon completion of the seam 25 and prior to movement of the work 31 toward the cutter 5, plate 8 returns to its initial position, underthread 4 is guided by edges 12, 12' and 13 into the slot 10 so as to come to rest between spring portion 15a and slot edge 18 as shown in FIG. 7. Next, the cutter assembly 24 operates on the underthread 4 and the upper run of cord 6 which has been deflected away from slot entrance 10' and onto the slightly curved upper face of plate 8 by the point 13' and the edge 15; this severing of the filaments 4 and 6 occurs close to the proximal end of scam 25.

As will be apparent from the drawing, particularly FIGS. 4 and 7, thread 4 and cord 6 are thereafter again disposed in such manner that the next step performed by needle 1' will interlink them with the upper thread 2 in the incipient formation of a new seam. This is true because both filaments 4 and 6 emerge from their respective guide passage 10, 8" substantially midway of the edge 15 of opening 8', thread 4 being thus readily positionable astride that opening by a suitable movement of the undertread-manipulating means 3 (see FIG. 4) irrespectively of the presence or absence of the cord 6.

What is claimed is:

1. In a buttonhole-sewing machine provided with a rotatable turret having feed means for supplying an underthread to a sewing location for co-operation with an upper thread carried by a reciprocable needle above said location, the combination therewith of a thoat plate on said turret provided with a needle-receiving opening at said location and with a slot communicating with said opening, said slot having an entrance end extending arcuately from said opening around the upper surface of said throat plate for admitting said underthread upon rotation of such turret, said slot cooperating with said feed means upon movement of said throat plate into a buttonhole, sewing position relatively to said needle for delivering said underthread to said needle-receiving opening, and resilient clamping means disposed at said slot for gripping engagement with said underthread.

2. In a buttonhole-sewing machine provided with a rotatable turret having means for supplying an underthread and a stay cord heavier than said underthread to a sewing location for cooperation with an upper thread carried by a reciprocable needle above that location, the combination therewith of a throat plate on said turret provided with a needle-receiving opening at said location and with a slot communicating with said opening, said slot having an entrance end extending arcuately from said opening around the upper surface of said throat plate for admitting said underthread upon rotation of such turret, and resilient clamping means disposed at said slot for gripping engagement with said underthread, said entrance end being wide enough to pass said underthread but sonarrow as to block entry of said stay cord into said slot, said throat plate being further provided with a channel for said stay cord communicating with both said slot and said opening, said clamping means including an element positioned to prevent entrance of said underthread into said channel.

3. The combination defined in claim 2 wherein said throat plate is formed with a shoulder, said slot and said channel being respectively provided with an outlet and an inlet at said shoulder, said outlet having the shape of a substantially horizontal slit and merging with said inlet, said element being angularly bent into a generally horizontal first portion and a generally vertical second por tion, said first portion extending along said outlet for clamping said underthread between itself and the upper edge of the slit, said second portion being disposed at the junction of said slit with said inlet.

4. The combination defined in claim 3 wherein said element has an extremity extending substantially at right angles to said shoulder, said throat plate being provided with a bore slidably accommodating said extremity and with fastening means for immobilizing said extremity in a selected position of adjustment.

5. The combination defined in claim 3 wherein said channel extends substantially perpendicularly to said shoulder toward an exit at said opening, the latter being formed with a cord-guiding edge extending substantially parallel to said shoulder adjacent said exit and being further formed with an underthread-guiding edge facing said exit and merging arcuately with an edge of said entrance end.

6. In a buttonhole-sewing machine provided with a rotatable turret having means for supplying an underthread and a stay cord heavier than said underthread to a sewing location for co-operation with an upper thread carried by a reciprocable needle above said location, the combination therewith of a throat plate on said turret provided with a needle-receiving opening at said location, said plate being further provided with a thread-receiving slot and with a cord-receiving channel communicating with said opening and merging into each other, and a resilient clamping element adjustably disposed at the junction of said channel with said slot for simultaneous gripping engagement with said underthread and said stay cord, said slot having an entrance end for said underthread wide enough to admit the latter but so narrow as to block entry of said stay cord into said slot.

References Cited by the Examiner UNITED STATES PATENTS 271,666 2/1883 Sullivan et a1 1l2253 X 757,463 4/1904 Hogan 1l2253 X 1,330,555 2/1920 Searle 112-71 1,787,928 1/1931 Carlson 112-253 2,324,235 7/1943 Pikul 112-71 2,778,329 1/1957 Howell et a1 l12l99 FRANK J. COHEN, Primary Examiner.

ROBERT V. SLOAN, Examiner. 

1. IN A BUTTONHOLE-SEWING MACHINE PROVIDED WITH A ROTATABLE TURRET HAVING FEED MEANS FOR SUPPLYIN AN UNDERTHREAD TO A SEWING LOCATION FOR CO-OPERATION WITH AN UPPER THREAD CARRIED BY A RECIPROCABLE NEEDLE ABOVE SAID LOCATION, THE COMBINATION THEREWITH OF A THROAT PLATE ON SAID TURRET PROVIDED WITH A NEEDLE-RECEIVING OPENING AT SAID LOCATION AND WITH A SLOT COMMUNICATING WITH SAID OPENING, SAID SLOT HAVING AN ENTRANCE END EXTENDING ARCUATELY FROM SAID OPENING AROUND THE UPPER SURFACE OF SAID THROAT PLATE FOR ADMITTING SAID UNDERTHREAD UPON ROTATION OF SUCH TURRET, SAID SLOT COOPERATING WITH SAID FEED MEANS UPON MOVEMENT OF SAID THROAT INTO A BUTTONHOLE, SEWING POSI- 